1955 johnson 25hp, pulling flywheel

[breeze]

I would like to pull my flywheel on my RDE17 to access the points and coils. Does anyone know the correct bolt size and thread pitch to thread into the flywheel for the puller? I know from reading here they should be grade 8, but my service manual doesn't say what size. Do I need 2 or 3 bolts? Also, will a steering wheel puller serve the purpose, or should I head out to the parts store?

I really want to get in there and replace the points and coils this weekend. When we checked for spark earlier on, the only way we could see one was with the plug grounded to the block, and it was orange (weak). Could not get it to show at all with a spark gap checker set at 7/16. I did a carb rebuild and it does run fairly well and pushes me around the lake ok, but I feel for a 25hp on a 14ft aluminum it should have a little more pep to it, and the RPM's don't really come up much higher from my half throttle start position to full throttle.

Thanks.

 

[F_R]

Re: 1955 johnson 25hp, pulling flywheel

The bolts are 1/4-20. Takes 3. Screw them into the flywheel 7/16", no more and no less. Then give it heck. If the puller breaks, get a better puller. 7/16" spark gap is kind of pushing it on that motor. Make it easy on yourself and just go for 1/4". You are looking for something that will start and run, not necessarily the max it can produce. When reinstalling the flywheel, have tapers clean and dry and use a torque wrench to tighten the nut to 60-65 ft/lbs. Can't stress the importance of this too much.

 

[BoatBuoy]

Re: 1955 johnson 25hp, pulling flywheel

7/16 is typically what's usually used for checking CDI ignition. They have a little hotter spark than the old point breaker magnetos.

 

[Chinewalker]

Re: 1955 johnson 25hp, pulling flywheel

Helps if the bolts are Grade 8s - less likely to snap...
- Scott

 

[breeze]

Re: 1955 johnson 25hp, pulling flywheel

Thanks for the info. I was able to get a puller from a friend of mine last night. Looks just like the one tashasdaddy had in a pic he had posted in another thread, so I think I should be good. And I already have a torque wrench, so I should be good to go. Should I hit the shaft with some liquidwrench or anything before i start pulling?

thanks again.

 

[F_R]

Re: 1955 johnson 25hp, pulling flywheel

A lot of people spritz something on it, but I really have serious doubts that it does anything other than make you feel like you are doing something. It is not frozen on the shaft, merely stretched so to speak. The parts are precision ground to a taper and when the nut is torqued to spec the tapers are mashed together so they don't slip. Nothing really gets into that tapered fit. The puller has to overcome that friction between the parts and give them a micro-slip apart. Then it will pop right off. Once you get it off you will find the parts as clean as they were the day they put it together. If it was done right that is.